学到了，楼主实现es6实现Set没考虑对象的键只能是字符串的问题，还有forEach()方法，第三个参数是mySet本身，这里改进了下楼主的代码： class mySet { constructor(optionsArr = []){ if(!(optionsArr instanceof Array)) throw Error('参数只能为数组') this.list = {} this.size = optionsArr.length optionsArr.forEach(val => { this.list[val] = val }) } add(val){ if(!this.list[val]) { this.list[val] = val this.size++ return true } return false } has(val){ if(val !== null &;&;typeof val === 'object') return false return this.list.hasOwnProperty(val) } delete(val){ if(this.list[val]) { delete this.list[val] this.size-- return true } return false } clear(){ this.list = {} this.size = 0 } keys(){ return Object.values(this.list) } values(){ return Object.values(this.list) } entries(){ return Object.entries(this.list).map(item => { item[0] = item[1] return item }) } forEach(callback){ let keys = this.keys() for(let i = 0;i<keys.length;i++) { callback(keys[i],keys[i],this) } } }